how do you say efficacy versus effectiveness in Portuguese? Hey, I am translating my doctoral thesis for practice and I ran into a problem where every dictionary I looked at gave the same word for two words that had a different meaning in my field. (eficaz is the word I kept getting). I need to explain how I am using them, as they are technical words in my field but also have non-technical uses. "Efficacy" and "Efficacious" (set 1) - when something works in a laboratory setting (for example "The treatment was efficacious for this disorder is..." or "in this efficacy study...") and "Effective" versus "Effectiveness" (set 2) - when something works in clinical real world setting (for example, "the treatment used in this clinical was not as effective as the efficacy studies would lead us to believe" and "Drift is one of the underlying factors in the rift between efficacy and effectiveness.") Thank you.